Do you know the best way to shield the coupling cap ?
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| Posted on July 1, 2012 at 08:40:04 | ||
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Posts: 49
Joined: October 31, 2001 |
The 300B amp I am building need a coupling cap of 0.33uF. When I place it closed to the 1st stage, it osclilate badly. Now I have to completely take it off from the chasis to eliminate the osc. I have been told to shield the coupling cap with "Conductor sheet wrapping around the cap" and then ground the conductor sheet to the ground. My question: (1) What is the theory for using only conductor (aluminium, copper etc) to shield the coupling cap. My previous experience in reducing the hum interference from the Power tranny to Output tranny was to use a Z11 silion steel sheet (same effect as Mu metal) to wrap around the power tranny and it worked. But only aluminium can do the job for the coupling cap? Is it a different secneraio ? (2) I have just been told that the way to WARP around the coupling cap should not be wrap the cap closely, instead of wrapping the cap closely by the conductor sheet it should be isolated from surrounding component. The reason heard is:: The conductor sheet closely touch around the coupling cap WOULD affect the behaviour of how this coupling cap work the way it should be.... Can you share you idea, since I do not know what is the best way to solve this problem as my coupling cap right now is placed outside of chasis. Regards Eric
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